'77 6 hp. Evinrude bogging down

[storyteller]

This one has me scratching my head. I recently bought a '77 Evinrude 6 hp. long shaft. I put it in my test barrel for the first time yesterday and it started great and idled great. I put it in gear and it ran great. I powered it up and after about half speed, it bogged down almost like it was running really rich or was running on one cylinder. So, I pulled the cover off and it cleared up and ran great at all speeds. Put the cover on and it acted up again. I've checked everything I can think of and can't come up with a reason. No loose wires, carb is clear of obstructions, etc. It only runs good with the cover off. I don't get it. Anyone have an idea?????????

Thanks!

 

[Daviet]

Re: '77 6 hp. Evinrude bogging down

If you have a blown base gasket it will leak exhaust at the base of the power head. With the cowel on the exhaust fills the cowel up and the engine cannot get air. To check this, removel cowel , run engine and squit some fogging oil into the carb and see if you see smoke at the base of the power head. You will have to run at a high idle RPM.

 

[storyteller]

Re: '77 6 hp. Evinrude bogging down

Thanks, I'll see what I can do.

 

[crxess]

Re: '77 6 hp. Evinrude bogging down

Check your throttle cam. Mine was bwdly worn and need adjustment to correct top end.